US 7396089 B2
The electro-pneumatic latching valve system having an electrical switch unit that further includes an “apply” or “activate” switch, a “release” or “deactivate” switch, and a power supply. A first solenoid valve is in electrical communication with the activate switch and a second solenoid valve is in electrical communication with the deactivate switch. A pneumatic latching valve is in pneumatic communication with the first and second solenoid valves and a source of pressurized control and supply air is in pneumatic communication with the pneumatic latching valve and the solenoid valves. A terminal device, e.g., a spring brake, is in pneumatic communication with the latching valve, and the device is released or applied in response to pressurized supply air delivered to the device through the pneumatic latching valve in response to pneumatic control signals delivered to the pneumatic latching valve from the solenoid valves.
1. An electro-pneumatic system for controlling the parking and emergency brakes of a vehicle, wherein the vehicle includes a tractor portion and a trailer portion, comprising:
(a) a driver interface subsystem, wherein the driver interface subsystem further comprises:
(i) a first electrical switch for operating the pneumatic brakes on the tractor portion; and
(ii) a second electrical switch in communication with the first electrical switch for operating the brakes on the trailer portion; and
(b) a brake control subsystem in electrical communication with the driver interface subsystem, wherein the driver interface subsystem further comprises:
(i) a remote module, the remote module further comprising a first electro-pneumatic valve unit in communication with the first electrical switch for controlling the supply and exhaust of pressurized air to/from the parking and emergency brakes of the tractor portion, for applying and releasing the parking and emergency brakes of the tractor portion, and a second electro-pneumatic valve unit in communication with the second electrical switch for controlling the supply and exhaust of pressurized air to/from the parking and emergency brakes of the trailer portion, for applying the releasing the parking and emergency brakes of the trailer portion; and
(ii) a tractor protection module in pneumatic communication with the remote module, the tractor protection module further comprising a means for controlling the parking and emergency brakes on the trailer and a means for preventing the delivery of pneumatic pressure to the trailer.
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(a) a first valve adapted to receive an electrical signal for opening the first valve, and wherein the first valve is further adapted to deliver a first pneumatic control signal when open;
(b) a second valve adapted to receive an electrical signal for opening the second valve, and wherein the second valve is further adapted to deliver a second pneumatic control signal when open; and
(c) a third valve in communication with the first and second valves, and wherein the third valve is adapted to receive pneumatic control signals, and wherein the third valve opens upon receiving the first pneumatic control signal and closes upon receiving the second pneumatic control signal.
13. A method for controlling a vehicle's pneumatic brakes, comprising the steps of:
(a) supplying pressurized control air to a first valve, wherein the first valve is in electric communication with a release switch for opening and closing the first valve;
(b) supplying pressurized control air to a second valve, wherein the second valve is in electric communication with an apply switch for opening and closing the second valve;
(c) supplying pressurized supply air to a third valve, wherein the third valve is in pneumatic communication with the first and second valves, and wherein the third valve is opened in response to control air received from the first valve, and wherein the third valve is closed in response to control air received from the second valve; and
(d) controlling the delivery of pressurized supply air to the pneumatic brakes, wherein the brakes are in pneumatic communication with the third valve, and wherein pressurized supply air received from the third valve releases the brakes, and wherein pressurized air exhausted from the third valve applies the brakes.
14. The method of
15. The method of
16. An electro-pneumatic system for operating a spring brake, comprising:
(a) a means for generating an electrical signal for opening a first valve, and wherein the first valve is adapted to deliver a first pneumatic control signal when open;
(b) a means for generating an electrical signal for opening a second valve, and wherein the second valve is adapted to deliver a second pneumatic control signal when open;
(c) a means for receiving the pneumatic control signals at a third valve, and wherein the third valve opens upon receiving the first pneumatic control signal and closes upon receiving the second pneumatic control signal;
(d) a means for delivering pressurized supply air through the third valve when open and into the spring brake for releasing the spring brake; and
(e) a means for exhausting the pressurized supply air from the spring brake when the third valve is closed for applying the spring brake.
This patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/449,710 filed on Feb. 24, 2003 entitled “Remote MV-3,” U.S. Provisional Patent Application Ser. No. 60/450,422 filed on Feb. 26, 2003 entitled “Remote MV-X (Provisional No. 2),” and U.S. Provisional Patent Application Ser. No. 60/466,820 filed on Apr. 30, 2003 entitled “Apparatus and Method for Electropneumatic Air Brake System,” the disclosures of which are incorporated as if fully rewritten herein.
This invention was not made by an agency of the United States Government nor under contract with an agency of the United States Government.
This present invention relates generally to braking systems for heavy-duty vehicles and more specifically to a valve system that utilizes a combination of electronics and pneumatics to operate the parking brakes and emergency brakes of a vehicle.
Conventional heavy-duty vehicle air brake systems typically use mechanical pneumatic push-pull control valves to control a vehicle's parking brakes. These large, pneumatic push-pull valves are usually placed within the vehicle's instrument panel, as are the pneumatic lines and connectors used to connect the brake control valves to the other components of the vehicle's air brake system. Dash mounting of these components may decrease pneumatic performance while consuming critical space in the vehicle's instrument panel which may ultimately result in dash configurations that are detrimental to the driver's comfort and convenience. Furthermore, installation of the pneumatic instrument panel controls requires complex, airtight connections during the final assembly phase of the vehicle. Thus, there is a need for a system that removes the pneumatic lines from a vehicle's dashboard while maintaining the basic functions and overall characteristics of currently used brake systems.
Some prior art braking systems have utilized electric controls to address the problem of limited dashboard space. Such systems typically include an electrical switch assembly mounted on or in the instrument panel for controlling the parking brakes with an electrically responsive valve located remotely from the dash components. One problematic aspect of these systems is that when electrical power is lost to the valve, the valve moves to its exhaust position, drops the parking brake line pressure to atmospheric pressure, and applies the vehicle's parking brake. Loss of electrical power or connectivity to a vehicle's brake system may be the result of loose terminal connections, broken wires, a dead battery, or other unforeseen events. As will be appreciated by those skilled in the art, inadvertent engagement of the parking brake may create an extremely dangerous situation if the vehicle is moving at any appreciable speed. Thus, there is a need for an air brake system that includes the use of electronics, but that prevents the inadvertent application of the vehicle's parking brakes should power to the brake control system be lost.
These and other disadvantages of the prior art are overcome by the present invention, which provides an electro-pneumatic system for controlling the parking and emergency brakes of a vehicle. The exemplary embodiment shown in the Figures utilizes a series of electrically controlled valves that are used to operate one or more pneumatic latching valves to apply or release a vehicle's parking brakes. Thus, the logic of this system and method of includes both electrical and pneumatic components.
The electro-pneumatic latching valve system of the present invention typically includes a switch unit having an electric “apply” or “activate” switch, a “release” or “deactivate” switch, and a power supply. In accordance with an exemplary embodiment, an electro-pneumatic latching valve unit includes a first valve is in electrical communication with the activate switch and a second valve is in electrical communication with the deactivate switch. A third valve, which is referred to herein as a “pneumatic latching valve” is in pneumatic communication with the first and second valves. A source of pressurized air is in pneumatic communication with all three valves in each valve unit. The first and second valves deliver control air to the latching valve in response to either an electric “apply” signal or an electric “release” signal and the latching valve opens or closes in response to these signals. A terminal device, such as a spring brake, is in pneumatic communication with the latching valve and is released in response to pressurized supply air delivered to the device through the open latching valve. The device is applied when the latching valve closes and the pressurized supply air is exhausted from the device through the latching valve.
In alternate embodiments of the present invention, the electro-pneumatic latching valve system is incorporated into the parking and emergency brake system of vehicles having the tractor and trailer configuration and vehicles having the truck configuration or mode. The electrically controlled valves are used only to induce a “change of state” in the vehicle's parking brakes, while the pneumatic latching valve is the system component that actually applies or releases the vehicle's brakes. Once the pneumatic latching valve has applied or released the parking brakes, any loss of electrical power to the valves or to the brake system, will not result in a change in the state of the vehicle's parking brakes, i.e., will not automatically apply the vehicle's parking brakes. As indicated previously, this aspect of the present invention is particular advantageous from a safety perspective.
Further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.
The accompanying drawings, which are incorporated into and form a part of the specification, schematically illustrate one or more exemplary embodiments of the invention and, together with the general description given above and detailed description of the preferred embodiments given below, serve to explain the principles of the invention.
The present invention provides an apparatus for use in controlling an air brake system and other pneumatic devices. The exemplary embodiment of the present invention utilizes a series of electrically controlled valves that are in turn used to operate at least one pneumatic latching valve to apply or release a vehicle's parking brakes. Thus, the logic of the system and method of the present invention includes both electrical,and pneumatic components. The electrically controlled valves, which in the exemplary embodiment are solenoid valves, are used only to induce a “change of state” in the vehicle's parking brakes, as described below. With reference to the Figures in general, a series of small capital letters are used to designate the ports of the various valves included in the system of the present invention. The letter “S” refers to “supply,” the letter “C” refers to “control,” the letter “D” refers to “delivery,” and the letter “E,” refers to “exhaust.” In the context of this invention, control air is used as a pneumatic signal that opens or closes a latching valve, while supply air is used to apply or release a terminal device such as a spring brake.
To distinguish the characteristics of the present invention from current state of the art pneumatic systems,
Primary reservoir air reservoir 120 and secondary air reservoir 122 supply pressurized air to the parking control valve unit 112 by way of supply lines 120 a and 122 a. Dash valve 114 represents the “yellow button” as it is referred to by those skilled in the art, and includes a combination park pneumatic push-pull plunger. Dash valve 116 represents the “red button” as it is referred to by those skilled in the art, and includes a trailer park control and air supply pneumatic push-pull plunger. The pneumatic logic present in this system enables buttons 114 and 116 to “pop” out automatically in the event the air reservoirs fail and fall below a prescribed pressure, such as, for example, about 40 psi for valve 116 (red) and about 20 psi for valve 114 (yellow).
Delivery line 130 a supplies pressurized air to spring brake 190, while trailer supply line 130 b supplies pressurized air to tractor protection module 140 and tractor protection valve 170. By way of primary delivery line 150 a or secondary delivery line 150 b, foot brake valve 150 delivers pressurized air to valve 170 directly or through double check valve 163. Likewise, trailer control valve 160 delivers pressurized air to valve 170 by way of delivery lines 160 a and 162. Tractor protection valve 170 may include a service line quick release valve and supply line quick release valve and delivers pressurized air to trailer supply line 172 and trailer service line 174 as well as stop light switch 180 by way of delivery line 180 a.
With reference to
In the exemplary embodiment shown in the Figures, terminal device 50 is a spring brake actuator that utilizes pressurized air to apply or release the parking brakes of a vehicle. With reference to
When the operator releases switch 14, valve 22 closes and airflow through the valve ceases. Pressurized air that was delivered to the control port of pneumatic latching valve 40 is exhausted through the exhaust port of solenoid valve 22. Although solenoid valve 22 is closed, and there is no air passing though the valve, the parking brakes of the vehicle remain released because pressurized supply air is still being delivered from reservoir 60 to the spring brake. Thus, valve 40 is referred to as a pneumatic “latching” valve because continuous current to the release valve is not required for the system to maintain continuous air flow to the terminal device. This aspect of the present invention is particularly advantageous over prior art systems because loss of electrical power or connectivity to the parking brake system does not automatically result in the application of the vehicle's parking brakes.
Again with reference to
When the operator releases switch 16, valve 30 closes and airflow through the valve ceases. Pressurized air that was delivered to the control port of pneumatic latching valve 40 is exhausted through the exhaust port of solenoid valve 30. Although solenoid valve 30 is closed, and there is no air passing though the valve, the parking brakes of the vehicle remain applied because no pressurized air is being delivered from reservoir 60 to the spring brake. As stated above, valve 40 is referred to as a pneumatic latching valve because continuous current to the apply solenoid is not required for the system to prevent air flow to the terminal system device. Again, loss of electrical power or connectivity to the parking brake system does not automatically result in a change of state in the vehicle's parking brakes.
Electro-pneumatic latching valve system 10 may be incorporated into larger, more complex tractor/trailer brake system.
As shown in
A button coupling diode 216 is situated between assemblies 212 and 214 and couples the function of the trailer and tractor components of the system. This coupling can be done with a diode or an equivalent device such as an electrical driver circuit that emulates the logic of a diode or may be implemented pneumatically with a check valve placed between the park sides of the yellow and red valves. Typically, the coupling logic utilized by a diode or other electronics is designed such that operating the park function of the yellow button unit automatically operates the park function of the red button unit. This functionality can be characterized as a “single-button park feature.” The electro-pneumatic system of the present invention functions such that if the two status lights on the valve unit are extinguished, then a single pull of the yellow button will pass current to both the yellow and red park solenoids, thus lighting both the red and yellow buttons once the parking action is complete.
In the exemplary embodiment shown in
The power for operating circuits 213 and 215 is provided by a power source 230, which is typically a 12V battery, and a capacitor 232 that is in electrical communication with both driver interface subsystem 210 and brake control subsystem 245. In the event of electrical power loss, capacitor 232 provides energy for at least one additional parking application; thus, the operator may still park the vehicle despite the loss of electrical power to the brake system. A diode or other isolation circuit may be employed to ensure that the capacitor's charge is preserved only for the parking system, and not discharged through the remainder of the vehicle electrical system. In alternate embodiments, a simple capacitor, a complex capacitive circuit, or other suitable means provides backup power. In general, power supply 230 and capacitor 232 comprise primary and secondary power supplies that provide the system with certain protections, conditioning, and backup emergency parking capability.
The embodiment shown in
With reference to
In the exemplary embodiment, “red” trailer supply valve 252 is situated above pneumatically latching trailer side valve 260 and “red” trailer park solenoid 254 is situated below valve 260; however, these two solenoids may be packaged together in a single housing and may reside on top of or between the latching valves. This combination of solenoids and pneumatic latching valve comprise the portion of the system that pneumatically operates the braking system of the vehicle's trailer (see
“Yellow” tractor park release solenoid valve 256 is situated above pneumatically latching tractor side valve 262 and “yellow” tractor park apply solenoid valve 258 is situated below pneumatically latching valve 262; however, these two solenoids may be packaged together in a single housing and may reside on top of or between the latching valves. In the exemplary embodiment, this combination of solenoids and pneumatically latching valve comprise the portion of the system that pneumatically operates spring brake 298, which is located in the tractor portion of the vehicle. Spring brake 298 is supplied with pressurized air by tractor spring brake delivery line 266.
In the embodiments shown in
In the exemplary embodiment, this pressurized air is supplied to the system by primary air reservoir 240 and/or secondary air reservoir 242. Primary supply line 240 a, which runs from primary air reservoir 240, and secondary supply line 242 b, which runs from secondary air reservoir 242 both connect to double check valve 243, which delivers the greater of the two input pressures. Dual air supply line 244 exits double check valve 243 and then branches into multiple supply lines that provide the solenoids and the pneumatically latching valves with pressurized control and supply air from supply line 244. As shown in
As shown in
As with the generic embodiment, when one or the other brake actuator control buttons (yellow and red buttons) is pushed in by the operator, electrical current flows to the solenoid valve located on top the pneumatic latching valve. The solenoid opens and delivers black or control air to the piston within the pneumatic latching valve. The pneumatically latching valve opens, delivering supply air to the terminal system component, e.g., the tractor spring brake. When the brake actuator is released, the top solenoid valve closes and air flow through the solenoid valve ceases, and air delivered to the top of the pneumatically latching valve is exhausted. However, the valve remains open and continues to deliver supply air to the spring brake. When a yellow or red button is pulled outward from the neutral position, the above-described process is reversed. Control air from the solenoid valve on the bottom of the pneumatically latching valve pushes the valve back to the closed position, thereby shutting off the air flow from supply to delivery, and exhausting pressurized air to atmosphere. Thus, as previously stated, even though the electrical power to the system may fail, the pneumatic latching valve remains in its most recent state, i.e., it does not automatically apply the parking brakes due to an electrical failure.
A number of variations are possible with the system of this invention. For example: (i) the solenoids may be assembled as a manifold at the vehicle's firewall such that all electrical connections are on the cab-side of the firewall and all the pneumatic connections are on the engine-side of the firewall; (ii) a time-delay circuit or strategy may be employed such that risk of unintended actuation of the parking brakes is reduced; (iii) the actuators can be any working switch logic, either driver-manipulated (push-pull buttons, flippers, sliders, dials) or coupled to another system (transmission shifter “park” position, for example); (iv) the system can receive additional logic, information, or control from an ABS ECU with the authority to control the brake system by a dedicated network protocol such as CAN; (v) the system may employ a dedicated ECU or the system may receive only advisory information, not command information, from an engine or chassis ECU other than an ABS ECU; (vi) the solenoid control may also be replaced by pneumatic pilot control using pneumatic valves that would emulate the operation of the 3-way/2-position, normally closed solenoids described above, e.g., the self-returning TH-3 (Bendix).
The present invention also provides a means for allowing safety interlocks to be integrated into a vehicle's brake system as simple electrical switch inputs. In general, the safety interlocks of the present invention (i) prohibit parking release based on information obtained from devices around a vehicle that indicates a safety concern regarding movement of the vehicle and/or (ii) force the vehicle into park based on information obtained from devices around a vehicle that indicates the driver, upon exiting the vehicle, has forgotten to park the vehicle. In the exemplary embodiment, safety interlock and theft deterrence are achieved simply by connecting existing vehicle switches (ignition key, brake light switch, door switch, safety belt switch, etc.) to an optional printed circuit board. The printed circuit board, if included, may be placed in an enclosure and may be located in the dash, integrated with existing buttons, or located on the in-the-cab side of the parking control subsystem.
In addition to air brake systems, the electro-pneumatic valve system of the present invention is compatible with any number of pneumatic systems in which a change of state is not desirable should electric power to the system or its components be lost. For example, this electro-pneumatic valve system may be used with a variety of pneumatic lift devices, including, but not limited to, powered doors, axle shifters, wheel chair lifts, cherry pickers, and air suspension systems.
While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as exemplification of certain preferred embodiments. Numerous other variations of the present invention are possible, and is not intended herein to mention all of the possible equivalent forms or ramifications of this invention. Various changes may be made to the present invention without departing from the scope or spirit of the invention.